Electronic apparatuses such as a modem or a power supply circuit are formed of a large number of electronic components. For instance, capacitors are often used for noise reduction or cutting a dc component.
Electronic apparatuses have been downsized and reduced their cost according to the market request, so that electronic components to be used in such apparatuses have also encountered the requests of substantial downsizing and cost reduction. Further, surface mount devices are often demanded because the automated mounting can reduce the mounting cost and save the mounting area. In parallel with the request of downsizing, contradictory requests have risen such as more sophistication, narrower dispersion of characteristics, and longer durability. In addition to the foregoing requests, LSIs equipped with multi-pins and signal lines handle more numbers of bits, so that plural electronic components should be mounted in a smaller area where narrower pitches of lines are routed, namely, a higher mounting density is needed. Many of the modems among others have a set of two lines, i.e. one for data input and the other for data output, so that two electronic components must be mounted one the lines.
However, downsizing and sophistication are the two contradictory goals, so that achievement of one goal has rejected the other goal. For instance, it has been proposed that an electronic component be packaged into a mold by packaging material such as resin in order to narrow the dispersion of performance or characteristics, or to improve the durability. However, in the case of mounting plural electronic components, since each component is molded by the covering material, the apparatus becomes bulky. Besides, since the molded component has greater dimensions, a greater space between signal lines is needed, so that the signal lines must be routed. Those reasons cause problems such as, the printed circuit board becomes bulky, line-radiation occurs, a signal delays due to the routing. As a result, the performance of the apparatus is degraded.
On the contrary, in the case of closely mounting bare electronic components, i.e. components without packaging into a mold, in order to achieve downsize and a high density mounting, problems also occur such as short between the components or cross-talk of signals due to electric field coupling. Those problems cause the electronic apparatuses to malfunction.
To overcome the forgoing problems, plural elements are packaged into molds and they are to be downsized, which results in narrower intervals between the elements, and terminals led outside the molds have an extremely narrow space therebetween, so that electrical insulating resistance between the terminals is lowered and leakage current is produced. As a result, the electronic component is damaged, which causes the apparatus to malfunction.
In the case of capacitive elements such as capacitors, electric field coupling occurs between the adjacent capacitors, and cross talk tends to occur easily, which causes noises. Those problems are critical for printed circuit boards of electronic apparatuses, many of which are equipped with a pair of lines for data input and data output.
In the case of packaging plural elements into one pack by a packaging material, the packaging material tends not to fill enough between the elements, so that a withstanding voltage between the elements lowers. When this package including plural elements undergoes a heat-cycle test, its durability becomes a problem. To overcome those problems causing lower performance, wider intervals between the elements must be reserved, which however inhibits electronic apparatuses from being downsized.